Is mythic war zone fire fight worth it ?
...for XP & RP? A: Yes
But, you may get annoyed by the difficulty; especially, when playing it solo. There’s a semi-decent chance that your random teammates won’t be fully committed to calling in powerful enough equipment to reach the end-round and earn a victory. In Mythic pretty much everyone needs to be willing to sell out for the victory by calling in the necessary vehicles, power weapons, etc. to earn a victory. There are some maps with late-game and end-game scenarios that are ridiculously difficult.
You’ll soon realize you probably only have a shot at earning a win under those scenarios if you have, or are lucky enough to be put onto, a particularly stacked and fully in sync fireteam with everyone having access and willing to use any and all necessary high end power weapons, vehicles, etc. to pull off a victory.